﻿<!DOCTYPE html>
<html>
	<meta charset="UTF-8"/>
	<head>
		<script>
			var n = 0;
			
			n = n+1;  //1
			n += 1;  //2
			n++; //3
			
			++n; //4
			//document.write( n++ ); //4
			//alert(n); //5
			
			//自增自减  分两种，前置和后置
			//前置：先加1，再使用
			//后置：先使用，再加1
			
			var k=1;
			var s = k + ++k + k++ + k + ++k;
			//	1 + 2 + 2 + 3 + 4
			alert(s);
			
			
		</script>
	</head>
	<body>
		
	</body>
</html>











